Electric switching arrangement



12, 1943- H. THOMMEN EIAL ELECTRIC SWITCHING ARRANGEMENT Filed May 28, 1941 xMxM I F E m f d 0% f m 0 0 dOv b 8 Patented Oct. 12, 1943 ELECTRIC SWITCHING ARRANGEMENT Hans Thommen and Alfred Halm, Baden, Switzerland, assignors to Aktiengesellschatt Brown, Boveri & Cie., Baden, Switzerland, a jointstock company of Switzerland Application May 28', 1941, Serial No. 395,691 In Switzerland June 8, 1940 3 Claims.

The invention relates to a switching arrangement, consisting of two circuit breakers connected in series, one of which connects into the circuit to be interrupted a damping device for reducing the current, whilst the other circuit breaker interrupts the residual current, a gas blast circuit breaker with multiple interruption being used for the former circuit breaker and an air isolating switch for the latter. In order to achieve an equal voltage distribution over all places of interruption of the power circuit breaker the current reducing damping means are so selected and dimensioned, that the air isolating switch in series with the gas blast circuit breaker may be employed for the interruption of the residual current which flows after the power switching points have been opened. The extinguishing chambers for the various points of interruption of the gas blast circuit breaker are made of insulating material and are provided with bottom and cover pieces preferably of metal, these being fitted with inlet openings through which the compressed gas flows to the extinguishing chambers and to the points of interruption, and outlet openings for the escape of the circuit breaker gases.

According to the present invention switching arrangements of the aforementioned kind are improved by providing closing devices for the passages through which the circuit breaker gases are conducted away from the points of interruption, these closing devices or valves being located at the outlet openings in the bottom and cover pieces of the extinguishing chambers. These closing devices enable a saving in compressed gas to be achieved and also have the advantage that when the contacts for the points of-interruption are open they are located opposite to each other under pressure.

In the drawing a constructional example of the invention is illustrated diagrammatically, Fig. 1 showing partly in section the assembly of an air blast circuit breaker with multiple interruption, whilst Figs. 2 and 3 show two constructional examples of extinguishing chambers in section.

The extinguishing chambers m to as each consist of an insulator cylinder am and a metal floor and cover plate carrying the contacts 'for the point of interruption located inside the extinguishing chamber. The floor and cover plates of adjacent extinguishing chambers are combined to form single constructional elements In, In, etc., containing a fixed nozzle contact and a movable contact d. These metal constructional elements arealso provided with ducts e1, e: for the passage of the air supply to the extinguishing chambers and points of interruption, whilst exhaust openings f1, f2, etc. are provided for the escape of the circuit breaker gases, as shown in Fig. 2. The movable contacts d of the points of interruption are arranged to slide under the action of a spring in a guide cylinder 9. In the wall of this cylinder 9 there is an air channel it which is in communication with the rear side of the piston of the valve 1'. This valve can either be arranged to move freely or under the action of a spring.

The actuating mechanism for each point of interruption is thus combined with a contact element of an adjacent point of interruption. The closing deviceor valve 1' is operated pneumatically. There is, however, of course nothing to prevent the closing device for a point of interruption from being operated mechanically in dependence on the movement of the adjacent point of interruption.

r Fig. 2 shows a point of interruption when the arcing contacts are in the closed position. When the circuit breaker blow valve not shown in the drawing opens, compressed air flows from the air container to the various extinguishing chambers (11 to as through the openings e1, e2, etc., and the movable contacts d are separated from the stationary nozzle contacts c against the action of their closing springs. The upper end of each movable contact d is provided with a slot (11 which after the contact has been moved a certain distance establishes communication between the extinguishing chamber and the space behind the valve i through the channel h, so that compressed air reaches the piston of valve 2 and closes this latter. Contacts 0, d are thus opened and located opposite to each other in the presence of compressed air. When the blow valv is closed and the supply of pressure gas to the extinguishing chamber is thereby stopped, the movable contacts d are returned towards closed positions by their closing springs as the pressure gas leaks from the extinguishing chamber. The slots d1 of the contacts d are thus moved out of communication with the passages h before contacts 0 and d reach closed position, and then each valve i is opened by the pressure of the gas still within the chambers, thereby venting the chamber to atmosphere.

Instead of arranging the closing devices (valves 1) at the points where the circuit breaker gases leave the metal constructional elements b1, b2, etc., it is also possible to locate the valves in the as a slide for the piston of the valve 1.

oil? the stationaryznozaie'c'ontacts in the manner illustrated in Fig 3. In this case the movable contact 11 of the points of interruption serves The movable contact d moves as before in a guide cylinder g which is in communication with the arcing chamber through a bore m in the wall The movable contact ct is again spring-loaded as in the previous embodiment of the cylinder.

shown in Fig. 2. In the wall of the movable contact d an air passage 'n'isprovided which connects the cylinder 9 with the hollow space inside the contact so thatcompressed air can reach the rear side of th piston of the valve 2'.

Also with this arrangement when the point of interruption is opened compressed air flows from the extinguishing chamber through the openings m, n to the rear side of the piston of the valve z and causes, after a-certain time interval required for the building up of gas pressure at the rear of the piston, the discharge of compressed air to stop. The valve 1 shuts 05 the discharge of compressed air through the hollow stationary ccntact.

We claim:

1. In a multiple break gas blast circuit breaker, a plurality of superposed arc extinguishing chambers comprising axially alined hollow insulating bodies and metal walf'members between adjacent insulating bodies, a set of arcing contacts within each chamber, one contact of each set being a pin contact, a cylindrical guide carried by one metal wall member of that chamber and slidably supporting the pin contact; the cooperating contact of that set being a nozzle contact carried by the other metal wall member of that chamber, spring means within each cylindrical guide normally retaining the pin contacts in engagement with the nozzle contacts, said meta1 wall members having blast exhaust passages extendingvfrom the associated nozzle'eontacts laterally to the" exterior of said wall members, meansincluding axial passages through said metal walhxnembers for the introduction of a gas under pressure to separate said pin contacts from the associated nozzle contacts, and valve means at each metal wall member and controlled by movements of the pin contact on that wall member for closing the blast exhaust passage of the nozzle contact of the same wall memebr; each valve means comprising a valve, a cylinder and piston supported by the wall member for operating said vave, and means including a passageway formed in part in said pin contact for introducing pressure gas into said cylinder from the arcing chamber in which the pin contact is located.

2. In a multiple break gas blast circuit breaker, the invention as recited in claim 1 wherein said cylinder of each valve means is on the Wall memher and at the exterior of the associated blast exhaust passage, and said valve closes the outlet end of the blast exhaust passage upon the introduction of pressure gas into the cylinder.

3. In a multiple break gas blast circuit breaker, the invention as recited in claim 1 wherein the cylinder and piston of each valve are Within the pin contact and cylindrical guide of the associated wall member, and the valve is within the same wall member to close communication between the nozzle contact and the blast exhaust passage.

, HAYS THOMMEN.

ALFRED HALM. 

